ubusd.c

   1 /*
   2  * Copyright (C) 2011-2014 Felix Fietkau <nbd@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <sys/socket.h>
  15 #include <sys/stat.h>
  16 #include <sys/uio.h>
  17 #ifdef FreeBSD
  18 #include <sys/param.h>
  19 #endif
  20 #include <syslog.h>
  21 #include <signal.h>
  22 #include <stdio.h>
  23 #include <unistd.h>
  24 #include <fcntl.h>
  25 #ifdef ENABLE_SYSTEMD
  26 #include <systemd/sd-daemon.h>
  27 #endif
  28
  29 #include <libubox/blob.h>
  30 #include <libubox/uloop.h>
  31 #include <libubox/usock.h>
  32 #include <libubox/list.h>
  33
  34 #include "ubusd.h"
  35
  36 static struct ubus_msg_buf *ubus_msg_ref(struct ubus_msg_buf *ub)
  37 {
  38         if (ub->refcount == ~0)
  39                 return ubus_msg_new(ub->data, ub->len, false);
  40
  41         ub->refcount++;
  42         return ub;
  43 }
  44
  45 struct ubus_msg_buf *ubus_msg_new(void *data, int len, bool shared)
  46 {
  47         struct ubus_msg_buf *ub;
  48         int buflen = sizeof(*ub);
  49
  50         if (!shared)
  51                 buflen += len;
  52
  53         ub = calloc(1, buflen);
  54         if (!ub)
  55                 return NULL;
  56
  57         ub->fd = -1;
  58
  59         if (shared) {
  60                 ub->refcount = ~0;
  61                 ub->data = data;
  62         } else {
  63                 ub->refcount = 1;
  64                 ub->data = (void *) (ub + 1);
  65                 if (data)
  66                         memcpy(ub + 1, data, len);
  67         }
  68
  69         ub->len = len;
  70         return ub;
  71 }
  72
  73 void ubus_msg_free(struct ubus_msg_buf *ub)
  74 {
  75         switch (ub->refcount) {
  76         case 1:
  77         case ~0:
  78                 if (ub->fd >= 0)
  79                         close(ub->fd);
  80
  81                 free(ub);
  82                 break;
  83         default:
  84                 ub->refcount--;
  85                 break;
  86         }
  87 }
  88
  89 static int ubus_msg_writev(int fd, struct ubus_msg_buf *ub, int offset)
  90 {
  91         static struct iovec iov[2];
  92         static struct {
  93                 struct cmsghdr h;
  94                 int fd;
  95         } fd_buf = {
  96                 .h = {
  97                         .cmsg_len = sizeof(fd_buf),
  98                         .cmsg_level = SOL_SOCKET,
  99                         .cmsg_type = SCM_RIGHTS,
 100                 },
 101         };
 102         struct msghdr msghdr = {
 103                 .msg_iov = iov,
 104                 .msg_iovlen = ARRAY_SIZE(iov),
 105                 .msg_control = &fd_buf,
 106                 .msg_controllen = sizeof(fd_buf),
 107         };
 108
 109         fd_buf.fd = ub->fd;
 110         if (ub->fd < 0) {
 111                 msghdr.msg_control = NULL;
 112                 msghdr.msg_controllen = 0;
 113         }
 114
 115         if (offset < sizeof(ub->hdr)) {
 116                 struct ubus_msghdr hdr;
 117
 118                 hdr.version = ub->hdr.version;
 119                 hdr.type = ub->hdr.type;
 120                 hdr.seq = cpu_to_be16(ub->hdr.seq);
 121                 hdr.peer = cpu_to_be32(ub->hdr.peer);
 122
 123                 iov[0].iov_base = ((char *) &hdr) + offset;
 124                 iov[0].iov_len = sizeof(hdr) - offset;
 125                 iov[1].iov_base = (char *) ub->data;
 126                 iov[1].iov_len = ub->len;
 127
 128                 return sendmsg(fd, &msghdr, 0);
 129         } else {
 130                 offset -= sizeof(ub->hdr);
 131                 return write(fd, ((char *) ub->data) + offset, ub->len - offset);
 132         }
 133 }
 134
 135 static void ubus_msg_enqueue(struct ubus_client *cl, struct ubus_msg_buf *ub)
 136 {
 137         if (cl->tx_queue[cl->txq_tail])
 138                 return;
 139
 140         cl->tx_queue[cl->txq_tail] = ubus_msg_ref(ub);
 141         cl->txq_tail = (cl->txq_tail + 1) % ARRAY_SIZE(cl->tx_queue);
 142 }
 143
 144 /* takes the msgbuf reference */
 145 void ubus_msg_send(struct ubus_client *cl, struct ubus_msg_buf *ub, bool free)
 146 {
 147         int written;
 148
 149         if (ub->hdr.type != UBUS_MSG_MONITOR)
 150                 ubusd_monitor_message(cl, ub, true);
 151
 152         if (!cl->tx_queue[cl->txq_cur]) {
 153                 written = ubus_msg_writev(cl->sock.fd, ub, 0);
 154                 if (written >= ub->len + sizeof(ub->hdr))
 155                         goto out;
 156
 157                 if (written < 0)
 158                         written = 0;
 159
 160                 cl->txq_ofs = written;
 161
 162                 /* get an event once we can write to the socket again */
 163                 uloop_fd_add(&cl->sock, ULOOP_READ | ULOOP_WRITE | ULOOP_EDGE_TRIGGER);
 164         }
 165         ubus_msg_enqueue(cl, ub);
 166
 167 out:
 168         if (free)
 169                 ubus_msg_free(ub);
 170 }
 171
 172 static struct ubus_msg_buf *ubus_msg_head(struct ubus_client *cl)
 173 {
 174         return cl->tx_queue[cl->txq_cur];
 175 }
 176
 177 static void ubus_msg_dequeue(struct ubus_client *cl)
 178 {
 179         struct ubus_msg_buf *ub = ubus_msg_head(cl);
 180
 181         if (!ub)
 182                 return;
 183
 184         ubus_msg_free(ub);
 185         cl->txq_ofs = 0;
 186         cl->tx_queue[cl->txq_cur] = NULL;
 187         cl->txq_cur = (cl->txq_cur + 1) % ARRAY_SIZE(cl->tx_queue);
 188 }
 189
 190 static void handle_client_disconnect(struct ubus_client *cl)
 191 {
 192         while (ubus_msg_head(cl))
 193                 ubus_msg_dequeue(cl);
 194
 195         ubusd_monitor_disconnect(cl);
 196         ubusd_proto_free_client(cl);
 197         if (cl->pending_msg_fd >= 0)
 198                 close(cl->pending_msg_fd);
 199         uloop_fd_delete(&cl->sock);
 200         close(cl->sock.fd);
 201         free(cl);
 202 }
 203
 204 static void client_cb(struct uloop_fd *sock, unsigned int events)
 205 {
 206         struct ubus_client *cl = container_of(sock, struct ubus_client, sock);
 207         struct ubus_msg_buf *ub;
 208         static struct iovec iov;
 209         static struct {
 210                 struct cmsghdr h;
 211                 int fd;
 212         } fd_buf = {
 213                 .h = {
 214                         .cmsg_type = SCM_RIGHTS,
 215                         .cmsg_level = SOL_SOCKET,
 216                         .cmsg_len = sizeof(fd_buf),
 217                 }
 218         };
 219         struct msghdr msghdr = {
 220                 .msg_iov = &iov,
 221                 .msg_iovlen = 1,
 222         };
 223
 224         /* first try to tx more pending data */
 225         while ((ub = ubus_msg_head(cl))) {
 226                 int written;
 227
 228                 written = ubus_msg_writev(sock->fd, ub, cl->txq_ofs);
 229                 if (written < 0) {
 230                         switch(errno) {
 231                         case EINTR:
 232                         case EAGAIN:
 233                                 break;
 234                         default:
 235                                 goto disconnect;
 236                         }
 237                         break;
 238                 }
 239
 240                 cl->txq_ofs += written;
 241                 if (cl->txq_ofs < ub->len + sizeof(ub->hdr))
 242                         break;
 243
 244                 ubus_msg_dequeue(cl);
 245         }
 246
 247         /* prevent further ULOOP_WRITE events if we don't have data
 248          * to send anymore */
 249         if (!ubus_msg_head(cl) && (events & ULOOP_WRITE))
 250                 uloop_fd_add(sock, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 251
 252 retry:
 253         if (!sock->eof && cl->pending_msg_offset < sizeof(cl->hdrbuf)) {
 254                 int offset = cl->pending_msg_offset;
 255                 int bytes;
 256
 257                 fd_buf.fd = -1;
 258
 259                 iov.iov_base = ((char *) &cl->hdrbuf) + offset;
 260                 iov.iov_len = sizeof(cl->hdrbuf) - offset;
 261
 262                 if (cl->pending_msg_fd < 0) {
 263                         msghdr.msg_control = &fd_buf;
 264                         msghdr.msg_controllen = sizeof(fd_buf);
 265                 } else {
 266                         msghdr.msg_control = NULL;
 267                         msghdr.msg_controllen = 0;
 268                 }
 269
 270                 bytes = recvmsg(sock->fd, &msghdr, 0);
 271                 if (bytes < 0)
 272                         goto out;
 273
 274                 if (fd_buf.fd >= 0)
 275                         cl->pending_msg_fd = fd_buf.fd;
 276
 277                 cl->pending_msg_offset += bytes;
 278                 if (cl->pending_msg_offset < sizeof(cl->hdrbuf))
 279                         goto out;
 280
 281                 if (blob_pad_len(&cl->hdrbuf.data) > UBUS_MAX_MSGLEN)
 282                         goto disconnect;
 283
 284                 cl->pending_msg = ubus_msg_new(NULL, blob_raw_len(&cl->hdrbuf.data), false);
 285                 if (!cl->pending_msg)
 286                         goto disconnect;
 287
 288                 cl->hdrbuf.hdr.seq = be16_to_cpu(cl->hdrbuf.hdr.seq);
 289                 cl->hdrbuf.hdr.peer = be32_to_cpu(cl->hdrbuf.hdr.peer);
 290
 291                 memcpy(&cl->pending_msg->hdr, &cl->hdrbuf.hdr, sizeof(cl->hdrbuf.hdr));
 292                 memcpy(cl->pending_msg->data, &cl->hdrbuf.data, sizeof(cl->hdrbuf.data));
 293         }
 294
 295         ub = cl->pending_msg;
 296         if (ub) {
 297                 int offset = cl->pending_msg_offset - sizeof(ub->hdr);
 298                 int len = blob_raw_len(ub->data) - offset;
 299                 int bytes = 0;
 300
 301                 if (len > 0) {
 302                         bytes = read(sock->fd, (char *) ub->data + offset, len);
 303                         if (bytes <= 0)
 304                                 goto out;
 305                 }
 306
 307                 if (bytes < len) {
 308                         cl->pending_msg_offset += bytes;
 309                         goto out;
 310                 }
 311
 312                 /* accept message */
 313                 ub->fd = cl->pending_msg_fd;
 314                 cl->pending_msg_fd = -1;
 315                 cl->pending_msg_offset = 0;
 316                 cl->pending_msg = NULL;
 317                 ubusd_monitor_message(cl, ub, false);
 318                 ubusd_proto_receive_message(cl, ub);
 319                 goto retry;
 320         }
 321
 322 out:
 323         if (!sock->eof || ubus_msg_head(cl))
 324                 return;
 325
 326 disconnect:
 327         handle_client_disconnect(cl);
 328 }
 329
 330 static bool get_next_connection(int fd)
 331 {
 332         struct ubus_client *cl;
 333         int client_fd;
 334
 335         client_fd = accept(fd, NULL, 0);
 336         if (client_fd < 0) {
 337                 switch (errno) {
 338                 case ECONNABORTED:
 339                 case EINTR:
 340                         return true;
 341                 default:
 342                         return false;
 343                 }
 344         }
 345
 346         cl = ubusd_proto_new_client(client_fd, client_cb);
 347         if (cl)
 348                 uloop_fd_add(&cl->sock, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 349         else
 350                 close(client_fd);
 351
 352         return true;
 353 }
 354
 355 static void server_cb(struct uloop_fd *fd, unsigned int events)
 356 {
 357         bool next;
 358
 359         do {
 360                 next = get_next_connection(fd->fd);
 361         } while (next);
 362 }
 363
 364 static struct uloop_fd server_fd = {
 365         .cb = server_cb,
 366 };
 367
 368 static int usage(const char *progname)
 369 {
 370         fprintf(stderr, "Usage: %s [<options>]\n"
 371                 "Options: \n"
 372                 "  -A <path>:           Set the path to ACL files\n"
 373                 "  -s <socket>:         Set the unix domain socket to listen on\n"
 374                 "\n", progname);
 375         return 1;
 376 }
 377
 378 static void sighup_handler(int sig)
 379 {
 380         ubusd_acl_load();
 381 }
 382
 383 int main(int argc, char **argv)
 384 {
 385         const char *ubus_socket = UBUS_UNIX_SOCKET;
 386         bool remove_socket = true;
 387         int ret = 0;
 388         int ch;
 389 #ifdef ENABLE_SYSTEMD
 390         int n_fds;
 391 #endif
 392
 393         signal(SIGPIPE, SIG_IGN);
 394         signal(SIGHUP, sighup_handler);
 395
 396         openlog("ubusd", LOG_PID, LOG_DAEMON);
 397         uloop_init();
 398
 399         while ((ch = getopt(argc, argv, "A:s:")) != -1) {
 400                 switch (ch) {
 401                 case 's':
 402                         ubus_socket = optarg;
 403                         break;
 404                 case 'A':
 405                         ubusd_acl_dir = optarg;
 406                         break;
 407                 default:
 408                         return usage(argv[0]);
 409                 }
 410         }
 411
 412 #ifdef ENABLE_SYSTEMD
 413         n_fds = sd_listen_fds(1);
 414         if (n_fds > 1) {
 415                 fprintf(stderr, "Too many file descriptors received.\n");
 416                 ret = -1;
 417                 goto out;
 418         } else if (n_fds == 1) {
 419                 server_fd.fd = SD_LISTEN_FDS_START + 0;
 420                 fcntl(server_fd.fd, F_SETFD, fcntl(server_fd.fd, F_GETFD) | FD_CLOEXEC);
 421                 fcntl(server_fd.fd, F_SETFL, fcntl(server_fd.fd, F_GETFL) | O_NONBLOCK);
 422
 423                 remove_socket = false;
 424         } else
 425 #endif
 426         {
 427                 unlink(ubus_socket);
 428                 umask(0111);
 429                 server_fd.fd = usock(USOCK_UNIX | USOCK_SERVER | USOCK_NONBLOCK, ubus_socket, NULL);
 430                 if (server_fd.fd < 0) {
 431                         perror("usock");
 432                         ret = -1;
 433                         goto out;
 434                 }
 435         }
 436         uloop_fd_add(&server_fd, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 437         ubusd_acl_load();
 438
 439         uloop_run();
 440
 441         if (remove_socket)
 442                 unlink(ubus_socket);
 443
 444 out:
 445         uloop_done();
 446         return ret;
 447 }